Internal-combustion engine



1,638,903 Aug. 1927' L. M. WOOLSON INTERNAL COMBUSTION ENGINE Filed May 3, '1923 2 Sheets-Sheet 1 37 anon doc L. M. WOOLSQ INTERNAL COMBUSTION ENGINE Filed May 5, 1923 2 heet 2 Patented Aug. 16, 1927.

UNITED STATES PATENT OFFICE.

LIONEI I. WOOLSON, OI DETROIT, MICHIGAN, ASSIGNOK 10 PACKARD MOTOR OAR I OOHPANY, O! DETROIT, IICHIGAN, A CORPORATION 01' MICHIGAN.

IITEBNAL- OOIBUBTION ENGINE Application fled lay 8,

The present invention relates to power mechanism for starting'hydrocarbon motors, and more particularly to that type of starter in which the motor thereof is connected to i 5 the driving pinion by means of epicyclic reduction gearmg. v

The gearing in starters of this type and particularly in starters for airplane engines, is subjected to sharply changing torques and loads. Thus when the engine is turned over from rest, a very heavy load and strain comes on the starter, and the load also varies throwing heavy shocks on the gearing, when the pistons of the engine are passing over the compression points. The gearing must be constructed of greater strength than would be required if there were no shocks of the kind mentioned above.

It is the principal object of the resent in- 2 vent-ion to provide means for e 'minating the efiect of the excessive stresses and shocks to which the gearing is subjected, so that the life of the gearing will be prolonged and at the same time a reduction in the weight and strength of the same may be obtained. According to the present invention this object is effected by mounting the reaction or stationary gear of the epicyclic train for rotation through a limitedangle, and providing yielding means for normally holding this gear in a definite position but permitti it to yield under excessive loads. Thus w en t the starting mechanism issubjected to the variable loads mentioned above, the normally stationary gear of the train yields, thereby absorbing the shocks and excessive stresses to which the gearing otherwise would be subjected, and eliminating to a ve eat extent the wear. and injury whic curred in the rigid gear trains heretofore em loyed.

nother object of the invention is tomount this yielding gear of the reducing train in such a manner that the gear together with its yielding means may be interchanged with the rigid gear now employed and its mount- %ther objects and features of novelty will be apparent from the following description taken in connection with the drawings in which: I v

Fi re 1 is a vertical longitudinal sectiona view throu h a starter mechanism constructed in accor ance with the present in- 1928. Serial I0. 886,482.

illustrated is of a well known type particularly emplo ed in connection with airplane engines. 'T e casing of the electric motor which operates the starter mechanism is designated by the numeral 10. The epicyclic gearing driven by the motor and transmitting the rotation thereof, at a greatly reduced rate to the driving pinion is housed in a frame 11 which is secured to the casin 10 by means of bolts 12. The armature sha t 13 of the motor projects into the housing 11 and has keyed thereto a beveled pinion 14, which meshes with a large bevel gear 15'. This large gear has a sleeve or hub secured to shaft 16 in any suitable manner as by being pinned thereto. Bi idly attached to gear 15, on each side thereo is ring 17, the two rings being secured co-axially with theshaft and in spaced relation to gear 15 by means of spacers 18 and bolts 19. The rin support a number of shafts 20 on each 0 which are journaled by roller bearings two integrally formed spur gears 21 and 22. The gears 21, which are of slightly greater diameter than the gears 22 mesh with an annular or internal gear 23 which is bolted in an annular recess in the inner face of a head 24.

The smaller spur or planet gears 22 mesh with an annular orinternal gear carried by a flange projectin from a nut member 43 which is journaled housing 11. A screw member 44 of steep pitch is mounted in the nut member and is adapted to be projected therefrom in a well known manner when the nut member is rotated by the gearing just described. This screw member 44 at its outer end carries rigidly therewith a spur pinion 60 which'is adapted to be thrown into mesh with the gear on the flywheel of the engine when the screw is projected. Mounted on the inner end of the screw 44 is a washer 45 which is adapted to seat against an annular face formed on a cover plate 46, when the screw is retracted; and mounted on the screw next to the washer isxa clutch disk 47 adapted to frictionally engage the nut member 43 when in a bearing 43in the the screw is projected b said nut, to clamp these parts together an thereby enable the pinion on the screw to drive the engine shaft.

The shaft 16, at one end, is mounted in a roller bearing 61 housed in the hub of the cover plate 46 and at the other end is mount ed in a ball bearing 62 carried by the head 24. A cover plate 48 screwed to the head 24 retains the outer race of the ball bearing in position, and the inner race ring of this bearmg issecured in position by a nut 49 on one side and a collar 50 on the other.

The mechanism thus far described is well known and except in so far as it is employed in combination, specifically forms no part of the present invention.

The improvement constituting the present invention consists in the provision of means for taking up the shock due to varying torques and loads, to which the gearing between the electric motor and the driving pinion is subjected. In the form of gearing illustrated herewith, this result is obtained by mounting the gear 23 for yielding rotative movement. Heretofore this gear has been rigid and unyielding. The means for yieldingly supporting this gear comprises the head 24 to which the gear 23 is rigidly secured by means of the cap screws 23. This head 24 consists of a disk-like web 25 and at its periphery has an inwardly extending cylindrical flange 26, being rotatively mounted within an annular member 27. The peripheral surface of the flange 26 and the corresponding bore of the annular member 27 are shouldered so as to prevent axial movement of the head 24 in an outward direction. The annular member 27 has anannular flange 28 fitted within an opening 28 in the housing 11, and also has a radial flange 29 which is clamped against the outer surface of the housing 11, by means such as the cap screws 27. This member 27 also includes an annular barrel portion 30.

Attached to the outer face of the head 24, by means such as the cap screws 31, is a plate 32 which has three equally spaced arms 33 projecting therefrom. From Figure 1 of the drawings it will be observed that the outer face of disk 32 is approximatel coplanar with the edge of the cylindrical ange 30, and so to provide for the passage of arms 33, this flange 30 is formed with recesses 34, providing shoulders 35 which areadapted to contact with the arms 33 and limit the rotary movement of head 24 in one direction. The movement of the head 24 in the other direction is limited by stop plugs 36 formed integral with barrel 30. Rotation of the head 24 and its disk 32 in one direction is yieldingly resisted by the springs 39 interposed between a washer 41 carried by a rod 37 secured to the arms 33, on the one hand, and an abutment 42 hearing against a lug 38 rigid with the annular member 27 on the other hand. The tension of the springs 39 may beadjusted b the nuts 41 threaded on the rods 37. As s own the abutments 42 have spherical seats 42 in the lugs 38.

This construction is such that when the gearing is subjected to an excessive torque or load, the annular gear 23 will yield rotatively to an extent depending upon the resiliency of the springs 39 and when the load returns to the normal or uniform amount, the springs will act to return gear 23 to its usual position. In this manner the effect of the shocks and stress to which the gearing has been subjected heretofore is eliminated.

The-yielding gear together with its mounting forms a closure for one end of the housing. In the known constructions this gear has likewise been mounted so-as to be carried by the closure for one end of the housing, but of course no yielding means were provided. The construction according to the present invention is such that the closure for the housing carrying the gear and its yielding means may be interchanged with the closure in the old constructions.

Although a specific embodiment of the invention has been described in detail it is to be understood that the invention is not thus limited but includes modifications and changes which come within the" scope of they appended claims.

Having thus described the invention what is claimed as new and desired to be secured by Letters Patent is:

1'. A starter for hydrocarbon engines, comprising in combination, anelectric motor, a pinion adapted to drive a ar on the engine, and an epicyclic reduction gearing between said motor and pinion including a yielding 1y mounted normally stationary gear adapted to yield under excessive loads.

2. The combination with, known engine v starter mechanism comprising an electric motor, a housing, a driving gear carried by said housing and adapted to mesh with a gear connected with an engine crank shaft, and reduction gearing in the housing connecting the motor and said driving gear; of a 010- sure for one end of said housing interchangeable with present closures, a gear mounted on said closure for limited rota movement and forming part of said reductlon gearing, and means on said closure yieldingly resisting rotation of said gear.

3. An electrically operated starter for hydrocarbon engines, comprising in combination, an electric motor having a casing, a housin bolted to said casing, a nut j ournaled in sai housing, a screw in said nut having a gear on the outer end thereof adapted to be projected into engagement with a gear on the engine clutch means to lock said nut and screw together, and a reducing gearing between said motor and nut comprising a normally stationary reaction gear yieldingly mounted in sai housing for limited rotary movement.

4. A starter for hydrocarbon engines, comprising in combination, an electric motor having a casing, a housing bolted to said casing, a bevel pinion fixed to the armature of said motor, a large bevel gear rotatably mounted in said housing and meshing with said pinion, a plurality of pairs of rigidly connected planet gears carried by said large bevel gear, an internal gear surroundin the larger gears of said pairs and mes 'ng therewith, means for mounting said internal gear for rotary movements in said housing comprisin a cylindrical head to the inner face of W ich said internal gear is fixed, and a barrel member havin a cylindrical portion fitting in an open si e of said housing and having a radial flange bolted to said housing, said head being rotatably mounted in said barrel member, stops on said barrel member adapted to limit the angle through which said head may rotate, springs yieldingly holding said head in a normal position and. adapted to yieldingly resist rotation of said head under the reactive forces exerted on said internal gear, a nut member journaled in said housing and having an annular flange formed with internal gear teeth meshing with the smaller gears of said pairs, and a screw operated by said nut having a gear fixed to its outer end adapted to be projected into engagement with a gear on the engine.

5. A starter for hydrocarbon engines, comprising in combination, an electric motor having a casing, a housing bolted to said casing, a bevel pinion fixed to. the armature of said motor, a large bevel gear rotatably mounted in said housing and meshing with said pinion, a plurality of pairs of rigidly connected planet gears carried by said large bevel gear, said gears of each pair differing in size, an internal gear surrounding the larger gears of said pairs and meshingtherewith, means for mounting said internal gear for rotary movements in said housing com prising a cylindrical head journaled in said housing to the innerface of which said internal gear is secured, a plate secured concentric with said head on the outer face thereof and having a plurality of arms projecting tangentially therefrom, rods pivoted to the outer ends of said arms, apertured lugs secured to said housing, said rods passing through said lugs, abutments secured to the outer ends of said rods and to said lugs, compression springs surrounding said rods and bearing at their ends against said abutments, a nut journaled in said housing and having an annular flange formed with internal gear teeth meshing with the smaller gears of said pairs, and a screw operated by said nut having a gear on its outer end adapted to be projected in engagement wit a gear connected to the engine.

6. A starter for hydrocarbon engines, comprising in combination, an electric motor having a casing, a housing bolted to said casing, a bevel pinion fixed .to the armature of said motor, a large bevel gear rotatably mounted in said housing and meshing with said pinion, a plurality of pairs of rigidly connected planet gears carried by said large gear, said gears of each pair differing in size, a normally stationary gear meshing with the larger gears of said pairs, means for mounting said normally stationary gear for rotary movements in said housing comprising a cylindrical head journaled in said housing to the inner face of which said normally stationary gear is secured, an arm secured to the outer face of said head and a spring interposed between said housing and arm, anut journaled in said housing, a gear connected to said nut and meshing'with the smaller gears of said pairs, and a screw operated by said nut having a gear on its outer-end adapted to be projected into engagement with a gear connected to the engine shaft. 1

In testimony whereof I hereunto aflix my signature.

LIONEL M. WOOLSON. 

